Menu psychology put to the real-life test: Can we persuade diners to order a vegetarian dish by changing the menu card?

It is not easy to select from a menu in a restaurant. Doubts may come up at the sight of the abundance of delicious choices. Do I want an appetizer, dessert or both? The menu card, also called the 'silent salesperson' is one of the most powerful tools that a restaurant has to market its dishes. Dozens of 'menu psychology' studies have shown that there are a number of ways in which diners can be influenced towards ordering more profitable items. For example, a field study showed that changing the description of food on a menu (e.g. ‘legendary chocolate mousse pie’) increased sales by 27%. 


Renske Hermans

But can we also use these psychological insights to encourage diners to order a vegetarian dish as a sustainable alternative to meat? Eating meat puts a lot of pressure on the environment. Could a restaurant menu card be used as an inexpensive and simple nudge to enhance consumer choices in the direction of societal best interest? That is; can we seduce diners to go for the vegetarian dish while eating out?

Renske Hermans took up the challenge to study this intriguing question for her master thesis project. This year, she is going to graduate from the Master Management, Economics and Consumer Studies at Wageningen University. In cooperation with Hotelschool The Hague we conducted a six-week field study in their fine dining restaurant 'Le Debut'. While enjoying organic and locally produced food in this restaurant, up to 50 guests are served by the school's international students. The kitchen is also run by hotel management students under guidance of instructors. 
 


Restaurant Le Debut at Hotelschool The Hague

After discussion with Chef Stefan, we decided to strategically place a tasty vegetarian dish at the heart of a so-called combo-menu including a starter, main course and dessert. We expected that this would lead to more sales of vegetarian dishes than placing them in the separate listing of menu items. In fast-food chains, 'combo-meals' are common options in which you get a pre-defined combination meal (sandwich, fries and drink) for a single price. For many consumers, they are an incentive to purchase something extra. It is similar to the practice of 'bundling' in retailing in which several items are sold for one price.

We called our combo-menu 'Menu Gastronomique', and developed one meat combo-menu and one vegetarian combo-menu. For the vegetarian menu, we took meat replacers of the famous Dutch ‘Vegetarian Butcher’, known for his innovative meat substitutes with a spectacular taste and texture. For two non-consecutive weeks, the vegetarian ‘Menu Gastronomique’ was available for €25.50. For a similar period and price, a meat ‘Menu Gastronomique’ was offered. As a control, we also had a 2-week period without any combo-menus, although diners could still select the same vegetarian and meat dishes. During these six weeks, we kept track of sales data. After dinner, we also asked diners to fill out a brief questionnaire about their dining experience and the menu card. 

Menu card in one of the periods of this nudge field study

Results of our study showed that dining in The Debut was a very positive experience for all customers. Across the entire six weeks, customers liked the menu and thought it provided good value for money. Some of the guest enthusiastically wrote about their dining experience at the questionnaire form. One diner wrote: ‘I was pleasantly surprised to have a vegetarian option! Very tasty’ and another diner commented on the vegetarian menu: ‘It looks delicious!”.


Unfortunately, our menu card nudge did not persuade a larger group of diners to go for the vegetarian dish. Less than one-fifth of the diners selected the vegetarian dish, and this number was not significantly different across the three menu card-periods. There are a few potential explanations. For example, it could be that we did not reach enough so-called ‘flexitarians’; meat-reducers who consume meat only several days a week. It might also be that this nudge was too gentle to convince diners to try something new. Previous research showed that meat replacers are typically seen as less tasty while at the same time dining out tends to grant people a license to indulge. Perhaps our nudge can seduce consumers in other settings, such as a workplace canteen.  

Kies mij! Een grappig volkorenbroodje als zetje naar de gezonde keuze

Volkorenbrood is gezond! Dat weten de meeste ouders en kinderen wel. Toch blijft wit  brood aantrekkelijk. Met name kinderen houden niet altijd van de grovere structuur, de smaak en eventuele zaadjes van volkorenbrood. Kinderen motiveren door ze te vertellen dat volkorenbrood goed voor ze is, is een riskante strategie. Recent onderzoek onder kleuters laat zien dat voedsel als gezond aanprijzen een averechts effect kan hebben. Als je maar vaak genoeg zegt ‘dit is gezond’ staat dat uiteindelijk voor hen gelijk aan ‘dit is dus minder lekker’.

Marketeers in de voedingsmiddelenindustrie zijn succesvol in het verleiden van kinderen door gebruik te maken van aantrekkelijke kleuren, vormen, tekenfilmhelden op de verpakking en ‘gratis’ cadeautjes. Deze marketingtechnieken worden helaas vooral ingezet om ongezonde producten te promoten. Kunnen we deze marketingtechnieken ook inzetten om kinderen een duwtje in de goede richting geven zonder wit brood te verbieden? Deze duwtjes worden ook wel nudges genoemd. De nudging aanpak wordt als veelbelovend beschouwd, omdat het op een slimme manier probeert de keuze omgeving van mensen te veranderen zonder deze keuze te beperken.

Kan een grappige vorm van brood kinderen verleiden om voor volkoren te kiezen?

Om deze vraag te beantwoorden hebben we (onderzoekers FBR en MCB) een veldstudie opgezet tijdens het Nationaal Schoolontbijt. Dit hebben we gedaan in samenwerking met het Nederlands Bakkerij Centrum (NBC). Tijdens dit landelijke evenement eten kinderen een ontbijt in hun eigen klas op school. Twaalf scholen deden mee aan ons veldonderzoek, elk met drie tot vijf klassen (groep 5 tot en met 8). De resultaten zijn onlangs gepubliceerd in het tijdschrift BMC Public Health.

De broodjes in verschillende vormen

Kinderen kozen uit een assortiment van witte en volkorenbroodjes. De broodjes zagen er niet allemaal hetzelfde uit. Broodjes werden zowel in grappige als normale vorm aangeboden volgens een experimenteel ontwerp. In sommige klassen waren de volkorenbroodjes gebakken in een grappige vorm (visjes, handje of hartje), net als de witte broodjes. In andere klassen waren ofwel de volkoren broodjes ofwel de witte broodjes grappig. Als controle hadden een aantal klassen alleen de keuze uit normale wit- en volkorenbroodjes. Op deze manier konden we precies nagaan of kinderen in dezelfde mate overstag gaan voor een grappige vorm in het geval van wit en volkorenbrood.

Per klas werd bijgehouden hoeveel broodjes er werden gegeten. De kinderen aten gemiddeld bijna drie broodjes, waarvan de meerderheid (76%) bestond uit wit brood. Het goede nieuws is dat vorm wel invloed had op de keuze voor een volkorenbroodje. Een leuke vorm van het volkorenbroodje maakte dat de keuze voor volkorenbrood verdubbelde (van gemiddeld een half broodje naar bijna een heel broodje). Het vaakst gingen kinderen overstag voor volkorenbrood als het wittebrood een gewone vorm had en het volkoren een grappige.

 

Kinderen waren enthousiast over de broodjes en namen vaak uitgebreid de tijd om de leukste vorm te kiezen. Dit plezier in kiezen bleek ook uit de ingevulde vragenlijsten na afloop. Het gehele ontbijt smaakte zelfs wat lekkerder als er grappige broodjes te kiezen waren.

Deze studie laat zien dat kinderen positief reageren op onze nudge. Dit kan vooral waardevol zijn als we kinderen willen helpen om te wennen aan iets nieuws. Herhaaldelijk aanbieden kan er vervolgens voor zorgen dat kinderen volkorenbrood meer gaan waarderen en dat het eten van volkorenbrood een vertrouwde gewoonte wordt.

How eating several smaller sized chocolates makes you look greedy and impulsive: the unit size effect of indulgent food

Imagine you are offered a package full of delicious chocolates. Would the size of the pieces of chocolate influences how much you eat?

Yes, the size of your piece of chocolate matters. This so-called unit size of food refers to the number of units in which a portion of food is divided. Earlier studies have shown that smaller units typically lead people to eat less. For example, Wansink and colleagues found that people being given four 100-calorie packs of crackers ate about 25% less than when given one 400-calorie pack. But why does this happen? Is it because everytime you start with a new piece, you realise you are still eating and wonder whether that is a good thing? A kind of pause moment? Or do other psychological processes play a role?

In a series of studies together with Hans van Trijp and Christos Kavvouris (published in Psychology and Health), we show that with a small unit size, people eat less because they have the impression (that others think) they eat more and are impulsive. Feeling or looking impulsive is something that many people want to prevent in our society.

Judging someone else eating chocolate (experiment 1)

In our first experiment, participants watched a movie featuring Michelle enjoying chocolate during a break. Half of the participants saw Michelle eating five small chocolates (about 50 grams in total). The other half of the participants saw Michelle eating exactly the same amount of chocolate, but now she ate one big chocolate bar. Interestingly, even though she ate the same amount of chocolate, participants considered the amount to be more excessive, impulsive and inappropriate in the case of the smaller pieces. 

 

Michelle eating 50 grams of chocolate in 5 small pieces (left) or 1 large piece (right)

 

Eating a fixed amount of chocolate (experiment 2)

In a second experiment, we asked one group of participants to eat all 5 small chocolates (50 grams) and another group to eat one entire large chocolate bar (50 grams). We asked them to imagine that they choose themselves to eat the amount they ate. Again, despite consuming the same amount of chocolate, eating smaller sized chocolates felt more excessive and inappropriate than eating one large piece.
 

Eating as much as you like (experiment 3)

Now participants got either 15 small-sized chocolates (150 grams) or 5 large-sized chocolates (also 150 grams) in a supposed taste test in which they were free to decide how much to eat. We also varied the wrapping of the chocolates (see picture below). Unwrapping a chocolate may draw attention to the decision to continue eating, which makes it less automatic.

About 23% less chocolate was eaten when it is presented in smaller units. Participants ate most in the groups being presented with unwrapped large chocolates. This unit size effect could be explained by people feeling more impulsive eating several smaller sizes chocolates than eating a large size chocolate.



Equal amounts of chocolate in the 4 conditions of study 3

Enjoy more, eat less
Across studies, the unit in which the chocolate was offered changed people's perceptions. Eating smaller units looks and feels more excessive and impulsive. Feeling more or less full had nothing to do with it. This brings us back to research on the numerosity effect in the 1990s. Essentially, we think that more pieces of something usually turn out to be more of something. In other words, bigger numbers equal bigger quantities. For example, a seven seater care is usually larger than a five seater car. A quick decision strategy that leads to good decisions most of the time, but it may also lead to wrong estimations.

Clearly, unit size is a cue that helps people to assess what an acceptable portion is. Smaller sized portions may help consumers to control themselves and eat less. Food companies could make item sizes smaller (indulgent snacks such as ice cream scoops or candies) or bigger (fruit, vegetables, whole wheat bread slices), depending on whether you want to make consumers effortlessly eat less or more.

van Kleef E., Kavvouris C. & van Trijp H.C.M. (2014). The unit size effect of indulgent food: How eating smaller-sized items signals impulsivity and makes consumers eat less, Psychology & Health, 1-41. DOI: 10.1080/08870446.2014.909426

What solutions do experts and students think of to get people to eat healthier? A summary of the Oslo workshop

This week I attended a workshop in Oslo in the beautiful building of the Norwegian Academy of Science and Letters. The aim of the workshop organized by our Food Ecology group of the Center of Advanced Studies was to come up with novel communication solutions to combat unhealthy eating habits. Guess what the typical ideas are that groups of participants came up with? First of all, apps and blogs are seen as a key solution to inspire consumers to change their behavior. The winning group came with an app for children that reward them for tasting new healthy foods. Other ideas were Facebook cooking pages and nutrition education campaigns targeting hard to reach consumers.

I admit that I am not objective, but I believe that our group came up with a very innovative nudge; a smart cap for sugary soft drink bottles that reduces the sip size. A study of Pascalle Weijzen and colleagues showed that smaller sip sizes lead to less consumption and quicker satisfaction. Our soft drink bottle concept also includes portion size indicators using clever sound and color sensors that indicate a suitable portion size. Enjoy more and drink less! However, one jury member called that 'a fantasy' and another jury member worried about Norwegian consumers traveling to Sweden to purchase cheaper soft drinks. Too bad...

Interestingly, when people are asked to come up with solutions, they first of all seem to think of the educational route to persuasion. This may be obvious, but Walls and colleagues wrote in their paper called 'Why education and choice won't solve the obesity problem' in the American Journal of Public Health: 'Although education and access to information are fundamental rights and are important in a democracy, they have a negligible impact on obesity'.

Anyway, it was fun to see how education is like the first intuitive way to go, even though it is getting more and more clear that focusing solely on increasing people's knowledge will not be sufficient in changing eating habits.